-4,5,6,7-Tetrahydro 3,6-dimethyl-3H-benzobfuran-2-one is a compound of use in perfumery and the field of flavorings, The compound can be used to impart a minty, slightly vanilla-scented odor, and its flavor imparts sweetness and roundness to the compositions to which it is added . Piping 1 having a fluid-mixing region M includes a reducer 5 including an end portion 5e disposed substantially on a central axis of a main pipe 2. A refrigerant circuit including a compressor and evaporator lines is operably connected to the cooling space of the inner housing.